In producing glass fibers for textile applications, an aqueous starch-oil type chemical treatment is applied to the glass fibers during their formation. This treatment protects the fibers from interfilament abrasion when a plurality of fibers are combined to make a strand and in any subsequent twisting operation. The aqueous chemical treatment applied during formation of the glass fibers is usually referred to as a sizing composition. The production of twisted glass fiber strands involves forming the stands and collecting one or more strands on a forming package and subsequently twisting the strands on the forming package on a twist frame and collecting the twisted strand or yarn on a bobbin.
As mentioned in U.S. Pat. No. 4,397,913 (Fahey) assigned to the same assignee as the present application, glass fiber strands used in the textile industry may be in the form of twisted, plied, braided or woven products. One type of glass fiber strand yarn has a single strand that is twisted, and plied yarns have several strands that are twisted together simultaneously. As mentioned in U.S. Pat. No. 4,397,913, glass fiber yarns are used to produce bulked yarns. The sizing composition plays a roll in the production of bulk yarns. It allows for a proper amount of integrity to protect the fibers prior to bulking but also allows for separation of one or more fibers when the yarn is contacted with fluid or air pressure to bulk the yarn as described in U.S. Pat. No. 4,397,913.
It is an object of the present invention to provide an aqueous starch-oil type sizing composition for glass fibers that results in good processing into and/or performance of bulked yarns.